In patients with American Society of Anesthesiologists physical status I and II, the risk of 30-day morbidity and mortality was similar for those who had blood testing shortly before surgery and those whose testing was done up to 2 months before surgery, this study finds.

Of 235,010 patients analyzed, 4,082 (1.74%) had at least one of the component morbidities or died within 30 days after surgery.

The incidence was:

1.7% when the most recent blood tests were measured within 1 week of surgery

1.7% when it was within 1 to 2 weeks

1.8% when it was within 2 to 4 weeks

1.7% when it was between 1 and 2 months

2.0% when it was between 2 and 3 months.

None of the values within 2 months differed significantly. The findings suggest that it is unnecessary to retest patients shortly before surgery, the researchers conclude.